Slide-valve gear for steam-engines.



No. 724,987. PATENTED APR. '7, 1903. S. S. YOUNGHUSBAND.

SLIDE VALVE GEAR FOR STEAM ENGINES.

APPLICATION FILED FEB. 25. 1903.

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SAMUEL SMITII YOUNGHUSBAND, OF DARLINGTON, ENGLAND, ASSIGNOR TO GILBERT CHARLES TVARD, SR, OF NEVVOASTLE, ENGLAND.

SLIDE-MAINE GEAR FOR STEAM ENGINES.

SPECIFICATION forming part Of Letters Extent No. 724,987, dated April '7, 1903.

Application filed February 25, 1903. Serial No. 145,092. (No model.)

T0 ctZZ whom it may concern:

Be it known that I, SAMUEL SMITH YOUNG- HUSBAND, engineer, a subject of the King of Great Britain, residing at Granville Terrace, WVoodlauds Road, Darlington, in the county of Durham, England, have invented certain new and useful Improvements in Slide-Valve Gear for Steam-Engines, of which the following is a specification.

My invention relates to slid e-valve reversing and expansion gear of the kind wherein motion is transmitted from the expansion and reversing link to the slide-valve through an intermediate lever which is pivoted to the die-block of the link and connected by its shorter arm or arms to the valve-rod, while its other and longer arm is pivoted to an arm or arms on the weigh-shaft, the expansion and reversing link vibrating as a whole about a fixed axis to which it is connected by a pair of swinging carrier-links and the reversal of the engine being effected by moving the dieblock along the slot of the link. This type of valve-gear, while specially designed to secure durability, cheapness, and compactness, gives a fixed amount of lead with all degrees of linking-up, a quick port-opening for the admission of steam, a quick opening at the commencement of exhaust, and a much larger steam-port opening and more sudden cut-off than usual for all degrees of linking-up, thus enabling the engine to be always readily started.

The invention is illustrated by way of example in the accompanying drawings, where- 1n- Figures 1 and 2 are a part sectional side elovation and a sectional end elevation showing the general arrangement of the improved gear as applied to' a locomotive havinginside cylinders and valve-chests, the gear being in midposition.

In the drawings, Ct b are the centers of the forward and backward eccentrics, respectively, and c the crank-center. The expansion and reversing link (1 is coupled to the forward and backward eccentric-rods e f by the pivotal joints 9 h, formed in or upon lugs situated at the back of the link toward the ends thereof. The link 61 is supported by being attached to the fixed axis 7 by means of a pair of swing carrier-linksj, which are pivotally connected at Z to gudgeons carried by a pair of brackets 7a, attached to the link d, the pair of ceutersl being in axial alinement and so placed as to intersect (either actually or approximately,as shown) the centerline of the expansion and reversing link slot at a point midway between the eccentric-rod joints g 71 The brackets 75 are fixed to the opposite faces of a lug 7r, projecting in the direction of the crank-shaft from the middle of the back memberof the link cl and in the plane of the link,the brackets being so formed as to overhang the link-slot and being offseta sufficient distance from the respective faces of the link 61 to allow of the die-block pin 1), the valve-operating lever 0,and the valve-rod 71 passing clear of the brackets and carrier-links j. In Fig. 1 the bracket 7r on the near side is broken The die-block m is fitted to slide in the slot of the link 01 and is coupled to the'valve-rod n by means of a lever 0, formed of duplex members, which work one at either side of the link d between the latter and the brackets 13. The lever 0 is pivoted, by means of the pin 19, to the die-block center and is fulcru med at q to an arm or arms 4" on the weighshaft 3, the lever 0 being continued beyond the die-block center p and pivoted at t to the valve-rod n, which is thus caused to reciprocate through a greater distance than if it were coupled direct to the die-block.

The expansion and reversing link cl may be curved in the direction shown, or in the op posite direction, or may be made straight, according to the position of the Weigh-shaft, as will be readily understood by any one versed in the art of designing link-motions. It is also to be observed that by suitably proportioning the length of the valve-rod n, the weigh-shaft arm 1, and the valve-operating lever o the constancy of the lead given by this gear to the slide-valve in all positions of the die-block may be maintained whatever the direction or degree of curvature given to the expansion and reversing link.

I claim-- In engine slide-valve gear of the kind described, the combination of a slotted expansion and reversing link having eyes situated away in section in order to show the lug 7c.

toward the opposite ends of the link-slot for the pivotal attachment of the eccentric-rods; a die-block fitted to slide in the link-slot and carrying a laterally-projecting pin for the pivotal connection of the valve-operating lever; a log projecting in the direction of the crank-shaft from midway of the length of the link and in the plane thereof; a pair of brackets fixed to the said lug at opposite faces thereof and projecting transversely of the link-slot at a snfficient distance from the opposite faces of the link to give passage to the die-block pin, the valve-operating lever pivoted to the die-block pin, and the valverod jointed to said lever; and a pair of axially-alined gudgeons, carried by and projecting from the brackets approximately in intersection with the middle point of the longitudinal center line of the link-slot, for the attachment of a pair of swing carrierlinks, as described.

SAMUEL Silll'lll YOU NGHUSBAND.

Witnesses:

ARTHUR J. TAYLOR, W. H. GOLDING. 

